Katsuhiko Takeuchi

Generalization of the binary interaction parameter of the Peng-Robinson equation of state by component family

Abstract Binary interaction parameters of the Peng-Robinson equation of state are successfully correlated in terms of the ratio of critical molar volumes and in addition absolute difference between the acentric factors of each component. The constants of a correlated function depend on some substance groups including chemically similar normal fluids. This correlation covers systems composed of hydrocarbons, carbon dioxide, nitrogen and hydrogen sulfide. VLE calculation for more than 100 binary and ternary systems showed excellent correlation. Improved prediction of vapor-liquid equilibria can be expected for these systems where little or no data is available.

Measurement and prediction of phase equilibria for the CO2-ethanol-water system

Abstract In relation to the concentration of ethanol solution from fermentation using near- or super-critical CO 2 extraction, vapor-liquid equilibria for the CO 2 -Ethanol-Water system were measured at 9.6, 17.2, 19.6, 25.0 and 32.0 °C up to 9 MPa in the wide range of ethanol concentration, including very dilute region (0.1–5wt%), where no data have been reported. A flow type apparatus equipped with a back pressure regulator was adopted for measurements in order to maintain the feed composition. From our experimental results, we concluded that, 1. 1) There are certain T and P conditions which give a maximum separation factor. 2. 2) In the low concentration region of ethanol, the distribution coefficient of ethanol is about 213 of the value in the higher ethanol concentration region. The measured data were compared with the results predicted by Patel-Teja equation and Group-Contribution equations of state (GC-EOS).

Solubility of PbO in supercritical water

Abstract Supercritical water(SCF-H2O) has been extensively used as a solvent to obtain finely divided powders of both crystalline and amorphous particles in the process called rapid expansion of the supercritical fluid solutions(RESS). Solubility data of inorganic substances in SFC-H2O are needed for a design purpose of the RESS process. However, so far the solubility data of inorganic substances in SCF-H2O near the critical point of H2O are very scarce. The purpose of this study is to provide the solubility data of PbO in SCF-H2O with the use of an one-pass flow apparatus. In order to check an experimental procedure, we also measured the solubility of SiO2 in SCF-H2O and compared the present results and the literature ones. The present results were analyzed with the hydration reaction model proposed by Wendelant and Glemser. The values of the degree of polymerization and solvation of PbO were determined.

Concentration of triethylene glycol, diethylene glycol and ethylene glycol in supercritical carbon dioxide up to 16 MPa at 313. 15 and 333. 15K

Abstract The concentrations of triethylene glycol (TEG), diethylene glycol (DEG) and ethylene glycol (EG) in supercritical carbon dioxide (CO 2 ) up to 16 MPa at 313. 15, and 333. 15K were measured by a vapor recirculation method. The concentrations of these glycols increase with increasing pressure and markedly increase from about 8 MPa at 313. 15 K and from about 11 MPa at 333. 15 K. A plot of the concentration of TEG, DEG and EG vs the density of pure CO 2 shows a gradually increasing curve. Also the concentrations were in the order of the vapor pressures of the glycols. The data were correlated using the following three methods: 1) Modified Redlich—Kwong (MRK) equation, 2) Peng—Robinson (PR) equation, 3) virial equation. From the results, it was found that the MRK equation gave a better fits than 2) or 3). However the correlation by the modified Peng—Robinson (MPR) equation proposed by Mohamed et al. gave almost the same results as the MRK equation.

Vapor-liquid equilibria for multicomponent systems containing methanol-acid gases 1. The solubility of inert gases in methanol

Abstract Vapor-liquid equilibria were measured by a vapor circulation method for systems containing CO2, H2S, COS, H2, N2, CO, CH4 and CH3OH in the region −50° to 0° and up to 70 bars. It was found that the solubilities of gases in multicomponent systems deviate from the values estimated from binary data. The solubility of inert gases in methanol for multicomponent systems is much greater than that in a binary system due to the influence of carbon dioxide and carbonyl sulfide. However, almost no such influence was detected in the case of hydrogen sulfide.

Excess molar enthalpies for 1-propanol + acetone and 1-propanol + acetone + benzene mixtures at 298.15 K

Abstract Excess molar enthalpies for the 1-propanol + acetone and 1-propanol + acetone + benzene systems have been obtained using a flow microcalorimeter. The experimental values have been correlated with polynomial equations and compared with the predicted results derived from an association model with mole-fraction-based equilibrium constants and binary parameters alone.

Measurement and correlation of solubilities of oxygen in aqueous solutions containing salts and sucrose

Abstract The solubilities of oxygen in aqueous solutions containing salts and sucrose were measured by a saturation method. The salts studied here are sodium chloride, ammonium sulfate, dipotassium hydrogenphosphate and potassium dihydrogenphosphate. These salts and sucrose are key components contained in fermentation media. The measurement were carried out at 298.15, 303.15 and 310.15K, because these temperatures are close to the fermentation condition. The extended scaled-particle theory proposed by Hu et al.(1985) was used to correlate the solubilities of oxygen in those solutions measured in this work, 2-1 type electrolytes solutions and aqueous glucose solutions appeared in the literature. In most cases, the experimental solubilities can be correlated with good agreement.

Calculations of quaternary liquid—liquid equilibria by use of a new local composition model

Abstract A new local composition model with two adjustable parameters per binary can represent binary vapour—liquid equilibria with good accuracy. For a ternary mixture the model includes six binary parameters and three additional ternary parameters in order to fit the model to ternary liquid—liquid equilibria. An extended form of the model for a quaternary mixture is proposed to involve further four quaternary parameters. Calculated liquid—liquid equilibrium results for 12 quaternary systems apparently show the good performance of the new model.

The effect of pressure on the sol-gel transition of gelatin in aqueous 1-1 electrolyte solutions

Abstract In order to clarify the effect of hydrostatic pressure and added electrolyte on the sol-gel transition, the sol-gel transition of gelatin in aqueous electrolyte solution under high pressures was determined by measuring the melting temperature of the gels with a dropping ball method The concentration range of the gelatin solutions was from 9 g/L to 90 g/L, temperature range from 293 K to 313 K, and pressure range up to 500 MPa. The electrolytes used were NaCl,LiCl, and KCl at concentrations up to 1 mol/L. It was found that the gelatin gels were stabilized by pressure in the electrolyte concentration range studied, while the dependence of the electrolyte concentration on the melting temperature varied with pressure. A maximum was observed in the melting temperature versus electrolyte concentration curves at low electrolyte concentrations. For the systems containing NaCl and KCl, after passing the maximum the gel was stabilized again by the addition of the electrolyte at pressures higher than about 300 MPa. The values for the enthalpy, entropy and volume changes accompanying the gel formation were calculated from the Eldrige-Ferrys plot and the Clausius-Clapeyron equation.

Measurement and Correlation of Phase Equilibria if Aqueous Two-Phase Systems and Partition Coefficients by Enzymes

ABSTRACT Furuya, T., Nakada, K., Iwai, Y., Arai, Y. and Takeuchi, K., 1990. Measurement and correlation of phase equilibria of aqueous two-phase systems and partition coefficients of enzymes. Aqueous two-phase systems provide a successful method for separating biomolecules by extraction under mild condition. Nevertheless, the phase equilibrium data of aqueous two-phase systems and the partition coefficient data of biomolecules are scarce and it is difficult to correlate them quantitatively. In the present work, the phase equilibria for the dextran-polyethylene glycol-water aqueous two-phase systems are measured. The partition coefficients of enzymes are also measured. Further, the osmotic virial equation is used to correlate the phase equilibria of the aqueous two-phase systems and the partition coefficients of enzymes.